They were sporadically deploying them throughout the Job 1 builds of which January 31, 2012 was one. That was a later Job 1 build. They were officially made standard by the start of Job 2 production for 2012 (Mar. 5,12 and later), but they were already pretty much standard by late job 1.

It was apparently part of their plan to ramp up production of the shutter systems across the entire model range, not just the SE SFE.